<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>作用域链理解</title>
    <script>
        var a  = 10;
        function func(num1){
            //arguments
            var a = 100;
            return function(){
                console.log(a);
            }
        }

       var res =  func();
        res();   //100
        console.log(res);
    </script>
</head>
<body>

</body>
</html>